2Learning ObjectivesList the components of the cardiovascular system and explain the major functions of this system.Describe the important components and major functions of the bloodList the characteristics and functions of red blood cells.Describe the structure of hemoglobin and indicate its functions.Discuss red blood cell production and maturation.
3Learning ObjectivesExplain the importance of blood typing and the basis for ABO and Rh incompatibilities.Categorize the various white blood cells on the basis of structure and function.Describe the structure, function and production of platelets.Describe the reaction sequences responsible for blood clotting.
4SECTION 19-1 The Cardiovascular System: An Introduction
5The cardiovascular system Provides a mechanism for rapid transport of nutrients, waste products, respiratory gases and cells
7Blood Fluid connective tissue Functions include Transporting dissolved gases, nutrients, hormones, and metabolic wastesRegulating pH and ion composition of interstitial fluidsRestricting fluid loss at injury sitesDefending the body against toxins and pathogensRegulating body temperature by absorbing and redistributing heat
8The composition of blood Plasma and formed elements comprise whole bloodRed blood cells (RBC)White blood cells (WBC)PlateletsCan fractionate whole blood for analytical or clinical purposes
9Figure 19.1 The Composition of Whole Blood Figure 19.1a
10Figure 19.1 The Composition of Whole Blood Figure 19.1b
11Figure 19.1 The Composition of Whole Blood Figure 19.1c
12Hemopoiesis Process of blood cell formation Hemocytoblasts are circulating stem cells that divide to form all types of blood cellsWhole blood from anywhere in the body has roughly the same temperature, pH and viscosity
14Plasma Accounts for 46-63% of blood volume 92% of plasma is water Higher concentration of dissolved oxygen and dissolved proteins than interstitial fluid
15Plasma proteins more than 90% are synthesized in the liver Albumins 60% of plasma proteinsResponsible for viscosity and osmotic pressure of blood
16Additional Plasma Proteins Globulins~35% of plasma proteinsInclude immunoglobins which attack foreign proteins and pathogensInclude transport globulins which bind ions, hormones and other compoundsFibrinogenConverted to fibrin during clottingRemoval of fibrinogen leaves serum
18Abundance of RBCsErythrocytes account for slightly less than half the blood volume, and 99.9% of the formed elementsHematocrit measures the percentage of whole blood occupied by formed elementsCommonly referred to as the volume of packed red cells
19Structure of RBCsBiconcave disc, providing a large surface to volume rationShape allows RBCs to stack, bend and flexRBCs lack organellesTypically degenerate in about 120 days.
21HemoglobinMolecules of hemoglobin account for 95% of the proteins in RBCsHemoglobin is a globular protein, formed from two pairs of polypeptide subunitsEach subunit contains a molecule of heme which reversibly binds an oxygen moleculeDamaged or dead RBCs are recycled by phagocytes
24RBC life span and circulation Replaced at a rate of approximately 3 million new blood cells entering the circulation per second.Replaced before they hemolyzeComponents of hemoglobin individually recycledHeme stripped of iron and converted to biliverdin, then bilirubinIron is recycled by being stored in phagocytes, or transported throughout the blood stream bound to transferrin
26RBC Production Erythropoeisis = the formation of new red blood cells Occurs in red bone marrowProcess speeds up with in the presence of EPO (Erythropoeisis stimulating hormone)RBCs pass through reticulocyte and erythroblast stages
33Leukocytes Have nuclei and other organelles Defend the body against pathogensRemove toxins, wastes, and abnormal or damaged cellsAre capable of amoeboid movement (margination) and positive chemotaxisSome are capable of phagocytosis
34Types of WBC Granular leukocytes Neutrophils – 50 to 70 % total WBC populationEosinophils – phagocytes attracted to foreign compounds that have reacted with antibodiesBasophils – migrate to damaged tissue and release histamine and heparin
35Types of WBC Agranular leukocytes Monocytes - become macrophage Lymphocytes – includes T cells, B cells, and NK cells
37Differential count Indicates a number of disorders Leukemia = inordinate number of leukocytes
38WBC ProductionGranulocytes and monocytes are produced by bone marrow stem cellsDivide to create progenitor cellsStem cells may originate in bone marrow and migrate to peripheral tissuesSeveral colony stimulating factors are involved in regulation and control of production
39Figure 19.12 The Origins and Differentiation of Formed Elements PLAYAnimation: The origins and differentiation of blood cellsFigure 19.12
41Platelets Flattened discs Circulate for 9-12 days before being removed by phagocytes
42Platelet functions Transporting chemicals important to clotting Forming temporary patch in walls of damaged blood vesselsContracting after a clot has formed
43Platelet production (thrombocytopoiesis) Megakaryocytes release platelets into circulating bloodRate of platelet formation is stimulated by thrombopoietin, thrombocyte-stimulating factor, interleukin-6, and Multi-CSF
45Hemostasis Prevents the loss of blood through vessel walls Three phases –Vascular phasePlatelet phaseCoagulation phase
46Hemostasis Vascular phase Local blood vessel constriction (vascular spasm)Platelet phasePlatelets are activated, aggregate at the site, adhere to the damaged surfaces
47Figure 19.13 The Vascular and Platelet Phases of Hemostasis
48Coagulation phaseFactors released by platelets and endothelial cells interact with clotting factors to form a clotExtrinsic pathwayIntrinsic pathwayCommon pathwaySuspended fibrinogen is converted to large insoluble fibrin fibers
49Figure 19.14 The Coagulation Phase of Hemostasis Figure 19.14a
50Figure 19.14 The Coagulation Phase of Hemostasis Figure 19.14b
51Clot retraction Final phase of healing Platelets contract and pull the edges of the vessel together
52Fibrinolysis Clot gradually dissolves through action of plasmin Activated form of plasminogenClotting can be prevented through the use of drugs that depress the clotting response or dissolve existing clotsAnticoagulants include heparin, coumadin, aspirin, dicumarol, t- PA, streptokinase, and urokinase
53You should now be familiar with: The components of the cardiovascular system and its major functions.The important components and major functions of the blood.The characteristics and functions of red blood cells.The structure of hemoglobin and its functions.Red blood cell production and maturation.
54You should now be familiar with: The importance of blood typing and the basis for ABO and Rh incompatibilities.The various white blood cells.The structure, function and production of platelets.The reaction sequences responsible for blood clotting.